The mRNA levels of TG2 isoforms, hypoxia-inducible factor (HIF)-1α, p16, cyclin D1 and B1, as well as markers of cell proliferation/death, DNA damage, and cell cycle were examined in SH-SY5Y (non-MYCN-amplified) and IMR-32 (MYCN-amplified) neuroblastoma cells in hypoxia/reoxygenation conditions. This evidence concerns the gene CCND1 and neuroblastoma.